Amphibian planet: Six of the strangest

The harlequin tree frog (Rhacophorus pardalis) of Borneo lives high in the jungle canopy and can glide from tree to tree. Here, males compete for a female making a foam nest. When the eggs hatch, the tadpoles will fall into a pond below.

(Image: Chien Lee/Minden Pictures/FLPA)

The reticulated glass frog (Hyalinobatrachium valerioi) of Costa Rica has semi-transparent skin, making it really hard to spot against this leaf. Amphibians can use their skin for everything from breathing to absorbing water, but the downside of this is that skin infections can wreak havoc on them.

(Image: Hiroya Minakuchi/Minden Pictures/FLPA)

The Mexican burrowing toad (Rhinophrynus dorsalis) spends most of its life buried underground. It emerges only after heavy rain to breed, and feed on ants and termites. It is unusual in having no close living relatives – it is the only species in its family.

There is no scientific distinction between a frog and a toad, but popularly "toad" is used for frogs with drier, wartier skin.

(Image: Photo Researchers/FLPA)

Caecilians are amphibians that look like snakes. Most live underground and little is known about them. The misnamed "rubber eel" (Typhlonectes natans) of Venezuela is semi-aquatic, however, and often sold as an aquarium pet.

(Image: Photo Researchers/FLPA)

Found across western Europe, the great crested newt (Triturus cristatus) is a protected species in several countries because of its declining numbers. This aquatic larva will develop into a terrestrial juvenile before attaining adulthood. The males have jagged black crests along their backs – hence the name.

(Image: Rene Krekels/FN/Minden/FLPA)

The Chinese giant salamander (Andrias davidianus) is the world's largest amphibian, growing up to 1.8 metres long. They are tiny, though, compared to the biggest ever amphibian, the extinct 9-metre-long Prionosuchus. The giant salamander is critically endangered as a result of habitat loss, pollution and harvesting for Chinese medicine, but so far has not been affected by the killer strain of the Bd fungus.